Remove config lockfile support (#38011)

## What changed

- Remove effective-config lockfile export, replay, and validation from session startup.
- Remove the `debug.config_lockfile` settings and generated schema entries.
- Remove feature-config materialization helpers that were only used to create lockfiles.

GitOrigin-RevId: a8c07c1c06325b3ec3dae9a97c36c2488d37df25

codex-rs/core/src/session/session.rs

@@ -85,9 +85,6 @@ pub(crate) struct SessionConfiguration {
     /// Base instructions for the session.
     pub(super) base_instructions: String,
 
-    /// Compact prompt override.
-    pub(super) compact_prompt: Option<String>,
-
     /// When to escalate for approval for execution
     pub(super) approval_policy: Constrained<AskForApproval>,
     pub(super) approvals_reviewer: ApprovalsReviewer,
@@ -1100,17 +1097,6 @@ impl Session {
                 );
             }
             session_configuration.thread_name = thread_name.clone();
-            validate_config_lock_if_configured(
-                &session_configuration,
-                base_instructions_provenance.as_ref(),
-            )
-            .await?;
-            export_config_lock_if_configured(
-                &session_configuration,
-                thread_id,
-                base_instructions_provenance.as_ref(),
-            )
-            .await?;
             let mut state = SessionState::new_with_auto_compact_window_ids(
                 session_configuration.clone(),
                 initial_auto_compact_window_ids,